# US 6,005,163 A · Method for cementing an implant into bone

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- Number: US 6,005,163 A
- Document ID: US6005163A
- Status: Granted
- Kind: A
- Application number: 08/925,789
- Filed: 1997-09-09
- Granted: 1999-12-21
- Earliest claimed: 1996-03-08
- Assignees: AO-Forschungsinstitut Davos
- Inventors: Slobodan Tepic
- Web page: https://patentgrep.com/patent/US6005163A

## CPC

- A61B 17/8802: {Equipment for handling bone cement or other fluid fillers}
- A61F 2/0095: {Packages or dispensers for prostheses or other implants (for intraocular lenses A61F2/1691; for dental surgery A61C19/02)}
- A61F 2/30767: {Special external or bone-contacting surface, e.g. coating for improving bone ingrowth}
- A61L 24/001: {Use of materials characterised by their function or physical properties}
- A61L 24/06: obtained by reactions only involving carbon-to-carbon unsaturated bonds {(A61L24/043, A61L24/046 take precedence)}
- A61B 17/8836: {for heating, cooling or curing of bone cement or fluid fillers}
- A61B 2050/0017: {Chemical heating}
- A61B 2050/0018: {Electric heating}
- A61F 2/3662: {Femoral shafts}
- A61F 2/3676: {Distal or diaphyseal parts of shafts}
- A61F 2002/4631: {the prosthesis being specially adapted for being cemented}
- A61F 2002/465: {using heating means}
- A61F 2002/4685: {by means of vacuum}
- A61L 2430/02: for reconstruction of bones; weight-bearing implants
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)

## Abstract

In this method for cementing an implant into bone by means of an autopolymerising two-component bone cement the implant, in particular the stem of a hip prosthesis is preheated above room-temperature prior to its cementing into bone, preferably to at least 43.degree. C. By this method the stem-cement interface is warmer than the bone-cement interface and consequently a stiff cement shell will form first around the stem and the cement will shrink towards the stem and away from the bone. The resulting reduction of porosity at the stem-cement interface improves significantly the fatigue life of the system.

## Claims

### Claim 1

A method for cementing an implant into bone by placing an autopolymerising cement on or in the bone to be treated and placing the implant in contact with said cement so that a layer of said cement remains between the implant surface and the bone, said cement comprising at least a monomer and a polymerization initiator, wherein polymerization of said cement is caused to start first at the implant/cement interface and wherein the surface of said implant is caused to be hotter that the surface of said bone at the onset of polymerization.

### Claim 2

A method for cementing an implant into bone by placing an autopolymerising cement on or in the bone to be treated and placing the implant in contact with said cement so that a layer of said cement remains between the implant surface and the bone, said cement comprising at least a monomer and a polymerization initiator, wherein polymerization of said cement is caused to start first at the implant/cement interface and wherein a layer of said initiator is applied to the surface of the implant prior to polymerization.

### Claim 3 (depends on 1)

The method according to claim 1, wherein said implant is preheated ex vivo prior to cementing said implant into said bone.

### Claim 4 (depends on 3)

The method according to claim 3, wherein said implant is preheated above a room temperature of 23.degree. C.

### Claim 5 (depends on 3)

The method according to claim 3, wherein said implant is preheated to at least 20.degree. C.

### Claim 6 (depends on 3)

The method according to claim 3, wherein said implant is preheated above normal body temperature.

### Claim 7 (depends on 3)

The method according to claim 3, wherein said implant is preheated to at least 43.degree. C.

### Claim 8 (depends on 3)

The method according to claim 3, wherein said implant is preheated to at least 44.degree. C.

### Claim 9 (depends on 3)

The method according to claim 3, wherein said implant is preheated to a temperature that is at least 6.degree. C. higher than the bone temperature of 37.degree. C.

### Claim 10 (depends on 1)

The method according to claim 1, wherein said bone is precooled prior to cementing said implant therein.

### Claim 11 (depends on 1)

The method according to claim 1, wherein said autopolymerizing cement is partial-vacuum-mixed and the implant is preheated.

### Claim 12 (depends on 11)

The method according to claim 11, wherein said cement is cooled to 5-10.degree. C. prior to cementing said implant.

### Claim 13 (depends on 1)

The method according to claim 1, wherein said cement is held at a temperature between 18 and 25.degree. C. prior to cementing said implant.

### Claim 14 (depends on 1)

The method according to claim 1, wherein said implant is placed in a package and heated by means of exothermically reacting chemical compounds.

### Claim 15 (depends on 14)

The method according to claim 14, wherein said exothermically reacting chemical compounds comprise hydrated sodium acetate (C.sub.2 H.sub.3 NaO.sub.2.3H.sub.2 O).

### Claim 16 (depends on 14)

The method according to claim 14, wherein said exothermically reacting chemical compounds comprise sodium thiosulfate pentahydrate (NaS.sub.2 O.sub.3.5H.sub.2 O).

### Claim 17 (depends on 1)

The method according to claim 1, wherein said implant is preheated to at least 50.degree. C.